This invention relates to data processing systems.
British Patent Specification No. 1 497 676 describes a search processor designed to perform search operations on a stream of data, so as to retrieve data items that satisfy a predetermined criterion. For example, the search processor may retrieve data items which contain a field equal to a specified key value.
Such a search processor may be connected to a conventional general purpose host computer. When the host requires a search to be performed, it sends a command to the search processor, specifying the criterion for the search, and the area to be scanned, and instructing the search processor to begin the search. The search processor then carries out the search, and returns retrieved data to the host computer as required.
The use of a specialized search processor enables search operations to be performed very rapidly, and provides a significant improvement in performance compared with conventional software search techniques.
One such specialized processor that is commercially available is the CAFS search processor, manufactured by International Computers Ltd.
A problem with the use of such a search processor is how it is to be integrated with the host computer. This conventionally requires customization of the host-peripheral interface, in terms of hardware, protocols, and operating system software. One object of the present invention is to overcome or alleviate this problem.